my company finally decided to switch from Office 2010 to Office 365. I had a lot of 2010 notebooks on my hard drive. I copied the complete notebook folder to my OneDrive. After refreshing the browser it switched my old notebook files to one new file. I could open them again and was happy that it is that easy. Few days later I tried it again, but it did not work till today. I have the old 2010 notebook with several files in one folder and cannot open the notebook online. When I click the "notebook.onetoc" file I get an error message that it cannot be opened. I cannot find a solution. My old 2010 OneNote client cannot be connected online. I found a thread with an "OneNote Importer" - this doesn´t work as well. Maybe you had the same task, I would appreciate any help. Thanks in advance!